1. Field of the Invention
This invention relates to a photographic camera for use with a new type of standardized film cassette, which is different from the "DX-code system" film cartridge, that has been recently standardized.
2. Description of Related Art
A new type of film cartridge, which is loaded in a photographic camera of the invention, has been standardized for an advanced photographic system (APS). For the purpose of providing an understanding of the new type of film cartridge, reference is made to FIGS. 12A and 12B. Generally, the film cartridge includes a generally cylindrical light-tight cartridge shell 30 in which a roll of a fresh filmstrip 34 wound on a spool 32 rotatable inside the film cartridge 30 is loaded at the manufacturer. The cartridge shell 30 has a light block door 36 which is rotated closed to prevent ambient light from entering the interior of the cartridge through a film egress/ingress slot as film is taken out of the camera or until it is placed in the camera, and which is then rotated open to allow the filmstrip 34 to move into and out of the cartridge interior through the film egress/ingress slot.
This new type of film cartridge 30 has what is called a visual exposure index (VEI). That is, the film cartridge 30 at one of its ends is provided with a data disk 38 rotating together with the spool 32. The data disk 38 has optically readable bar codes of various information concerning the filmstrip 34, such as the type of film, the speed or sensitivity of film and the number of exposures, printed on its outer surface. The film cartridge 30 at another one of its ends is formed with four cut-outs 40, 42, 44 and 46 differently shaped in the forms of circle, square, cross and semicircle, respectively. A tongue-shaped white indicator (not shown) rotatable together with the spool 32 is located on a side of the cartridge interior and is viewed through one of the respective cut-outs 40, 42, 44 and 46 from the exterior of the film cartridge 30 according to angular positions. Specifically, the white indicator viewed through the circular cut-out 40 provides an indication that the filmstrip 34 is fresh. The white indicator viewed through the square cut-out 42 provides an indication that the filmstrip 34 has been photo-processed. The white indicator viewed through the cross cut-out 44 provides an indication that the filmstrip 34 has been fully exposed but is not photo-processed. The white indicator viewed through the semicircular cut-out 46 provides an indication that the filmstrip 34 is partly exposed and partly unexposed.
The filmstrip 34 has a silver salt photosensitive layer coated on one surface 34.sub.F of the film base and a magnetic recording layer on another surface 34.sub.R of the film base. The filmstrip 34 also has magnetic tracks 52 and 54 coated along and on opposite sides of each film frame 48 on the one surface 34.sub.F of the film base and perforations 50 formed to define opposite ends of each film frame 48. Information on exposure, such as the type of exposure light, the focal length, etc., and the title of a picture are magnetically recordable on and readable from the magnetic tracks 52 and 54 at the photographer's request.
The film cartridge 34 has an optically readable bar code 56 indicating its own identification number (ID number) printed on the outer surface thereof.
When a camera of the APS type is loaded with the film cartridge 34, the camera automatically reads the optically readable data, such as the bar codes, on the data disk 38 by means of an optical reader incorporated therein. While the camera automatically opens the light block door 36, it also automatically detects an angular position of the white indicator to automatically advance the filmstrip 34 out of the film cartridge 34 until a first unexposed film frame is placed in the camera exposure frame if the filmstrip 34 is fresh or partly exposed. On the other hand, if the filmstrip 34 is fully exposed or has been photo-processed, the camera judges from the angular position that the filmstrip 34 is unavailable, and holds the filmstrip 34 in the interior of the film cartridge 30.
When the filmstrip 34 is fully exposed, while the camera rewinds the exposed filmstrip 34 into the interior of the film cartridge 30, it aligns the white indicator with the cross cut-out 44 and locks it, and closes the light lock door 36. When unloading the film cartridge 30 from the camera, the film cartridge 30 shows the white indicator through the cross cut-out 44, indicating to the photographer or persons handling the film cartridge 30 that the filmstrip 34 in the film cartridge 30 is fully exposed. When the filmstrip 34 is intentionally rewound into the interior of the film cartridge 30 after it is partly exposed, the camera aligns the white indicator with the semicircular cut-out 46 and locks it, and closes the light lock door 36. When unloading the film cartridge 30 from the camera, the film cartridge 30 shows the white indicator through the semicircular cut-out 46, indicating to the photographer or persons handling the film cartridge 30 that the filmstrip 34 in the film cartridge 30 is partly exposed.
As described above, the new type of film cartridge has various novel features, such as a magnetic information recording and reproducing feature, in addition to features of the conventional film cartridge. Further, the new type of film cartridge enables photographers not only to visibly recognize the exposed state of the filmstrip 34 preserved therein even if the filmstrip 34 is exposed, fully or partly, or has been photo-processed, but also to use different types of films by turn with a single camera of the APS type, which is hardly realizable by the conventional DX-code system film cartridges.
In cases where the new type of film cartridge is used together with a conventional camera, when the film cartridge with a partly unexposed filmstrip 34 contained therein is reloaded in the conventional camera, it is impossible to read the magnetically recorded information on the magnetic tracks of the filmstrip 34, and the features accompanying the new type of film cartridge, such as automatic positioning of a first unexposed film frame of the filmstrip 34, are not applicable.
In order for a camera for use with the new type of film cartridge to read magnetically recorded information on the magnetic tracks, it is necessary to incorporate a highly sensitive and highly precise magnetic head which is generally large in size and needs its associated parts and elements including complicated circuits and operation switches. While it may be possible to enter an ID No. of a film cartridge into the camera without using such a magnetic head, entering an ID No. of a film cartridge whenever the film is intentionally rewound halfway imposes a somewhat troublesome operation on the photographer when rewinding a film halfway for the purpose of photo-processing.
While the film cartridge containing a film with film frames partly unexposed is visually recognized to be partly exposed and partly unexposed through the VEI, it is not known how many unexposed film frames the film in the cartridge has unless the film cartridge is loaded in the camera. Loading and unloading a film cartridge in a camera so often is undesirable in view of durability.